class Employee:
    # 类变量，用于记录实例化的对象数量
    instance_count = 0

    def __init__(self, name, position):
        self.name = name
        self.position = position
        # 每次实例化时，类变量加1
        Employee.instance_count += 1

    @classmethod
    def get_instance_count(cls):
        # 返回实例化的对象数量
        return cls.instance_count

    def sayHello(self):
        # 实现 sayHello 方法
        print(f"Hello, my name is {self.name} and I am a {self.position}.")

class CEO(Employee):
    def __init__(self, name, position, company):
        super().__init__(name, position)
        self.company = company

    def sayHello(self):
        # 调用父类的 sayHello 方法
        super().sayHello()
        # 添加 CEO 特定的问候
        print(f"I am the CEO of {self.company}.")

# 示例用法
if __name__ == "__main__":
    emp1 = Employee("Alice", "Engineer")
    emp2 = Employee("Bob", "Designer")
    emp3 = Employee("Charlie", "Manager")

    print(f"总共实例化的员工对象数量: {Employee.get_instance_count()}")

    ceo = CEO("David", "CEO", "TechCorp")
    ceo.sayHello()